pinckaers



Aug. 11, 1959 B. H. PINCKAERS TRANSISTOR CONTROL APPARATUS OriginalFiled Dec. 29, 1954 A. C. SUPPLY INVENTOR B. H. PINCKAERS ATTORNEY Re.24,678 Re'issued Aug. 11, 1959 United States Patent Ofifice TRANSISTORCONTROL APPARATUS Balthasar H. Pinckaers, Edina, Minn., assignor toMinneapolis-Honeywell Regulator Company, Minneapolis, Minn., acorporation of Delaware Original No. 2,872,595, dated February 3, 1959,Serial No. 478,469, December 29, 1954. Application for reissue February4, 1959, Serial No. 791,241 7 12 Claims. (Cl. 307-885) Matter enclosedin heavy brackets appears in the original patent but forms no part ofthis reissue specification; matter printed in italics indicates theadditions made by reissue.

This invention rel-ates to transistor control apparatus and morespecifically to a new and improved transistor discriminator circuit. Thetransistor discriminator circuit which provides an AC. output is soconstructed that the input and output transformers previously requiredin discriminator circuits of this type have been eliminated. Theinvention describes a transistor control apparatus which supplies AC.power to a load device when the input signal potential is of one phase,proportional to the magnitude of the signal potential, and supplies nopower to the load when the signal is of the opposite phase.

An object of the invention is to provide an improved and simplifiedtransistor discriminator circuit which is selectively responsive to anAC. signal potential to produce an AC. output proportional in magnitudeto the signal.

Another object of the invention is to provide a transistor discriminatorcircuit which has no input or output transformer and which provides anAC. output to a load device.

These and other objects of the present invention will be understood uponconsideration of the accompanying specification, claims and drawings ofwhich the single figure of the drawing is a schematic diagram of theimproved transistor discriminator circuit comprising the invention.

Referring now to the single figure of the drawing there is shown atransformer 10 having a primary winding 11 connected to a suitablesource of alternating current and having secondary windings 12, 13 and14. Secondary winding '12 is connected by conductors 15 and 16 to inputterminals 20 and 21 of a resistance bridge circuit 17. The bridge 17comprises fixed impedance members 22, 23, 24, and a condition responsiveimpedance member 25, which may be, for example, a temperature responsiveelement such as a NTC resistor. The bridge has a pair of outputterminals 26 and 27, the former being connected to ground 30 by a groundconductor 31. The bridge is connected to control a transistor amplifierstage which comprises a transistor 32, shown for illustrative purposesas a p-n-p transistor. The transistor 32 includes a collector electrode33, an emitter electrode 34 and a base electrode 35. The emitterelectrode 34 is connected to ground by a conductor 36 and conductor 31.Base electrode is connected to output terminal 27 of bridge 17 by aconductor 37. Collector electrode 33 is connected to a terminal of asource of negative potential through a conductor 40, a resistor 41 and aconductor 42. A base bias resistor 29 is connected between junction 28on conductor 37 and a junction 47 on the conductor 42. The source ofnegative potential 46 includes secondary winding 13, a diode rectifier43, and a filter capacitor 44. The positive side of the potential sourceis connected to ground potential. A pair of output transistors 50 tive.

and 51 are controlled by the output of transistor 32. Transistor 50 hasa collector electrode 52, an emitter electrode 53, and a base electrode54, and transistor 51 has a collector electrode 55, an emitter electrode56 and a base electrode 57. A pair of diodes 60 and 61, which may begermanium diodes, are connected in series with emitter electrodes 53 and56 respectively by conductors 62 and 63. Emitter electrode 53 isconnected to base electrode 57 through conductor 62, diode 60, aconductor 63,'a junction 64, and a conductor 65, likewise emitterelectrode 56 is connected to base electrode 54 through conductor 63,diode 61, a conductor 66, a junction 67 and a conductor 68. Base 54 andemitter 56 are connected to the previous stage transistor collectorelectrode 33 by a capacitor '70 connected between junction 67 and ajunction 38 on conductor 40. Base electrode 57 and emitter electrode 53are connected to emitter electrode 34 of transistor 32 by a conductor 71connected between junction 64 and a junction 39 on conductor 36.Secondary winding 14 of the transformer 10 has a terminal 18 connectedto the collector electrode 55 of transistor 51 by a conductor 72. Aterminal 19 of the winding 14 is connected to the collector electrode 52of transistor 50 through a conductor 73, a suitable load device 74, anda conductor 75.

OPERATION In the drawing there is shown a null balance system. A.C.bridge 17 is energized by transformer winding 12. Assuming a conditionsuch that the bridge is balanced there is no signal from outputterminals 26 and 27 of the bridge. If conditions change so thatcondition responsive resistor 25 increases in resistance, an outputsignal of one phase will result, and if the conditions change in theopposite direction so that resistor 25 decreases, an output signal ofthe reverse phase will result. The A.C. output signal from the bridge isfed to the input of transistor 32, which is biased class A. The bridgesignal is applied across emitter 34 and base 35 and results in anamplified alternating component being impressed on the DC. currentflowing in the collector circuit and through resistor 41. Thealternating signal is coupled to the discriminator stage throughcoupling capacitor 70. Transistor stage 32 merely providessignalamplification and may be omitted if desired. The discriminator stagecomprising transistors 50 and 51 is arranged to provide a full Wavealternating output to a load directly without the use of input andoutput transformers.

Let us assume an instantaneous polarity of the source such that terminal18 of transformer winding 14 is negati ve with respect to terminal 19.Let us also assume the instantaneous signal potential at junction 67 isposi- Current will tend to flow from terminal 19 through load device 74,through the low impedance collector-base junction of transistor 50 inthe forward direction, or direction of easy current fiow, throughconductors 68 and 66, diode '61 in the forward direction, conductor 63to the emitter 56 of transistor 51. Since we assumed a signal potentialsuch that base 57 is negative with respect to emitter 56, the transistoris biased to conduct easily cur rent and the load current flows throughthe transistor and from collector 55 through conductor 72 to terminal 18of the Winding 14. The diode 60 in the emitter circuit of transistor 50prevents any current from flowing out of the emitter circuit during theportion of the cycle transistor 50 is acting as a diode from collector52 to base 54. On the succeeding half cycle terminal 18 becomesinstantaneously positive with'respect to terminal 19 of transformerwinding 14. Now current tends to flow from terminal 18 through conductor72 to collector 55 of transistor 51, through the collector-base junctionin the forward direction, through conductors 65 and 63, through diode 60in the forward direction, conductor '62 to emitter 53 of transistor 50.The instantaneous polarity of the signal having also reversed, function67 is negative with respect to ground so that base 54 is. negative withrespect to emitter 53 biasing transistor 50 for easy current flow. Theload current flows through the transistor, from col lector '52- throughconductor 75 to the load 74, and from the load through conductor 73 toterminal 19 of winding 14. Diode 61 prevents current from flowing out ofthe emitter circuit 56 during the portion of the cycle transistor 51 isoperating as a diode from collector 55 to base 57. Thus it is seen thatonly one transistor operates as a transister on each half cycle, theother operating as a diode.

The system is. a proportional system so that as. the signal unbalance.from bridge 11 increases, the larger becomes the current permitted toflow through the load 74'. The load device 74' which preferably is apro-portioning device, may for example, control the condition beingsensed by condition responsive resistor 25. As the condition beingsensed changes so that the. bridge 17' returns toward balance the signalmagnitude decreases reducing the bias to the discriminator stage and thecurrent flowing to the load 74 decreases. At a balanced condition of thebridge, with. no A.C. signal being applied to the discriminator theload. current is substantially' cut oit. A reverse condition from thatpreviously described unbalances the bridge in the opposite directionproducing a signal output of the opposite phase. When a signal of theopposite phase is applied to the input of the discriminator stage thetransistors remain cut off and. no current flows to the load. Thus witha signal of one phase applied a. full wave A.C. output results and witha signal of the opposite phase the load is not energized.

The transistors have been shown and described as p-n-p type, however,the invention. is not so limited and by proper consideration ofenergizing polarities and the direction which diodes 60 and 61 areconnected with respect to the emitters, any suitable transistor may beused. If the transistors 50 and 51 are n-p-n the diodes 60 and 61 mustbe connected to conduct in the opposite direction.

In general while. I' have shown a specific embodiment of my invention,it is. to be. understood that this is for the purpose of illustrationand that my invention is to be limited solely by the scope; otLthe.appended claims.

1 claim asmy invention:

1. Transistor discriminator. apparatus comprising: first. and secondtransistors, said first transistor having a first base, collector, andemitter, said second transistor having a second base, collector, andemitter; first and second asymmetrical conducting devices each having aninput and an output terminal, said output terminals of said first andsecond asymmertical conducting devices being directly connectedrespectively to said first and second emitters; a source of alternatingpotential means including load means connecting opposite terminals ofsaid potential source intermediate said first and second c01- lectors sothat said transistors are energized out of. phase; means directlyconnecting said first base to said second input terminal and directlyconnecting said second base to said first input terminal so that currentflowing; from said first base flows to said second emitter through saidsecond asymmetrical conducting. device; a source of alternating signalcurrent of variable magnitude and reversible phase, said signal currentsource being connected to said first and second transistors in. phaseopposition, so that with a signal of one phase both transistors willconduct current on alternate half cycles of said potential source.respectively, while. a signal of the. reverse phase prevents conductionof both transistors.

2 Transistor control apparatus comprising: first and: secondtransistors, each oi. said transistors. havingv a plurality ofelectrodes including a collector, an emitter, and.

a base electrode, two of said electrodes oi each transis tor comprisinginput terminals; direct current conductive means directly connectingsaid first transistor base electrode exclusively to said secondtransistor emitter electrode and directly connecting said secondtransistor base electrode exclusively to said first transistor emitterelectrode; a source of alternating potential; load means; circuit meansincluding said load means connecting the collectors of said transistorsto opposite. terminals of saidalternating potential; source so that saidtransistors. are energized in phase opposition; a first current paththrough said transistors, said path being between emitter and collector;a second current path through said transistors, said path being betweencollector and base, so. that during one half cycle current flows throughthe first current path of said first. transistor and the second currentpath of said second transistor and on the succeeding half cycle currentflows through said second current path of said first transistor andthrough said first current path of, said second transistor; and a sourceof signal current connected to said input terminals to control themagnitude of current fiow through said transistors.

3. Transistor control? apparatus: comprising: first and secondtransistors, each of said transistors having a plurality of electrodesincluding a collector, an emitter and.

a baseelectrode, two of said electrodes comprising the. input terminals;first and second asymmetrical conducting means, conductive. meansdirectly connecting the base. of said first transistor to the emitter ofsaid second. transistor through. said second asymmetrical conductingmeans; conductive means directly connecting said. base of said secondtransistor to the emitter of said first tran sistor through said; first.asymmertical conducting. means;

a source of alternating current potential; load means;

circuit means including said load means connecting the."

collectors of said transistors to opposite terminals of said potential:source; and means connecting a source of alternating signal potential tothe input terminals of said transistors to control the conduction ofsaid transistors in response to said signal.

4. Control apparatus comprising: a pair of transistors, each of saidtransistors including a collector electrode, an emitter electrode and acontrol electrode; means including nonlinear impedance means directlyconnecting the emitter electrode of a first of said transistors to thecontrol electrode of the second of said transistors, and directlyconnecting the emitter electrode of said second transistor to thecontrol electrode of said first transistor; a source of alternatingcurrent potential; load means; circuit means including said load meansdirectly connecting the collector electrodes of said first and secondtransistors respectively to opposite terminals of said source; and asource of alternating current signal potential connected to control thecurrent flow through said transistors.

5. Control apparatus comprising: first and second. transistors, each ofsaid transistors having a collector electrode, a base electrode and anemitter electrode, two of said electrodes comprising input terminals;conductive coupling means directly connecting together the firsttransistor emitter electrode to the second transistor base electrode andalso directly connecting together the second transistor emitterelectrode to the first transistor base elecrode; a source of alternatingpotential; means 6. Transistor control apparatus comprising: a. signal.

current source of variable magnitude and reversible phase;

a pair of transistors each having. a plurality of electrodes. includinga collector, an: emitter, and a base; conductive.

means directly connecting the base electrode of the first of saidtransistors to. the: emitter electrode of. the second. of saidtransistors; and also directly connecting the. base electrode of saidsecond transistor to the emitter electrode of said first transistor;output means; a source of alternating potential; means including saidoutput means connecting said collectors to opposite terminals,respectively, of said source of alternating potential; circuit meansconnecting said signal current source to the emitter and base electrodesof said transistors, said signal being applied in opposite sense to eachof said pair of transistors in such manner that a signal current of onephase controls conduction of said transistors so that a substantiallycontinuous current flows through said transistors to said output means,while a signal current of the opposite phase substantially cuts offcurrent flow to said output means.

7. Transistor control apparatus comprising: a signal current source ofvariable magnitude and reversible phase; a pair of transistors eachhaving a plurality of electrodes including a collector, an emitter, anda base, at least one of said included electrodes of each transistorcomprising output terminals; a pair of said included electrodes of eachtransistor comprising input terminals; conductive means directlyconnecting the base electrode of the first of said transistors to theemitter electrode of the second of said transistors, and also directlyconnecting the base electrode of said second transistor to the emitterelectrode of said first transistor; output means; a source ofalternating potential; means including said output terminals to oppositeterminals, respectively, of said source of alternating potential, saidpotential having a frequency corresponding to the frequency of saidsignal current source; circuit means connecting said signal currentsource in phase opposition to said input terminals of each of saidtransistors in such manner that a signal current of one phase controlsconduction of said transistors so that a substantially continuouscurrent flows through said transistors to said output means, while asignal current of the opposite phase substantially cuts off current flowthrough said transistors to said output means.

8. A circuit arrangement comprising a pair of transistors, each havingan emitter electrode, a collector electrode, a base electrode, onemitter-collector path and a collector-base path, means for connectingthe emittercollector path of one of said transistors in series with thecollector-base path of the other of said transistors, means forconnecting the collector-base path of said one transistor in series withthe emitter-collector path of said other transistor, means forcontrolling the electrical admittance of said emitter-collector pathscomprising a first electrical signal source connected between theemitter and base electrodes of said transistors, a second electricalsource, means for deriving an output signal connected in series circuitarrangement with said second source, and means for coupling saidcollector electrodes comprising said series circuit arrangement.

9. A circuit arrangement comprising a pair of transistors each having anemitter electrode, a collector electrode, a base electrode, anemitter-collector path and a collector-base path, means for connectingthe emitter-collector path of one of said transistors in series with thecollector-base path of the other of said transistors including means forconnecting the emitter electrode of said one transistor to the baseelectrode of said other transistor, means for connecting thecollector-base path of said one transistor in series with theemitter-collector path of said other transistor including means forconnecting the base electrode of said one transistor to the emitterelectrode of said other transistor, a first electrical signal sourceconnected between said base electrodes, a second electrical source,means for deriving an output signal connected in series circuitarrangement with said second source, and means for coupling saidcollector electrodes comprising said series circuit arrangement.

10. A circuit arrangement comprising a first transistor and a secondtransistor, each having an emitter electrode, a collector electrode anda base electrode, a first junction point, means for connecting theemitter electrode of said first transistor to said first junction point,means for connecting the base electrode of said second transistor tosaid first junction point, a: second junction point, means forconnecting the emitter electrode of said second transistor to saidsecond junction point, means for connecting the base electrode of saidfirst transistor to said second junction point, a first electricalsignal source connected between said first and second junction points, asecond electrical source, means for deriving an output signal connectedin series circuit arrangement with said second source, and means forcoupling the collector electrode of said first transistor to thecollector electrode of said sec- 0nd transistor comprising said seriescircuit arrangement.

11. A circuit arrangement comprising a pair of transistors each havingan emitter electrode forming an input electrode system with a baseelectrode, a collector electrode, an emitter-collector path and acollector-base path, means connecting the emitter-collector path of eachof said transistors in series with the collector-base path of the otherof said transistors, a first electrical signal source connected in theinput electrode systems of said transistors, a second electrical source,means for deriving an output signal from said circuit arrangement, andmeans connecting said first-mentioned means in series circuitarrangement with said second source between the collector electrodes ofsaid transistors.

12. A circuit arrangement comprising a pair of transistors each havingemitter, collector and base electrodes, on emitter-collector path, anemitter-base path and a collector-base path, means connecting theemitter-collector path of each of said transistors in series with thecollector base path of the other of said transistors, a first electricalsignal source, means connecting said first signal source in series withthe emitter-base path of each of said transistors, a second electricalsource, means for deriving an output signal from said circuitarrangement and means connecting said last-mentioned means in seriescircuit arrangement with said second source between the collectorelectrodes of said transistors.

References Cited in the file of this patent UNITED STATES PATENTS2,622,212 Anderson et al Dec. 16, 1952 2,665,845 Trent Jan. 12, 19542,695,381 Darling Nov 23, 1954 2,728,857 Sziklai Dec. 27, 1955 2,778,978Drew Jan. 22, 1957 2,783,384 Bright et a1 Feb. 26, 1957 OTHER REFERENCESArticle, Symmetrical Properties of Transistors and Their Applications,Proceedings of the I.R.E., June 1953, by Sziklai.

